The present invention relates to a series of new isoxazolinone derivatives, to processes for preparing them and to insecticidal and acaricidal compositions containing these new derivatives.
Insects and acarids cause considerable damage to plants and can represent a serious danger to health; at best, they are a major nuisance. Accordingly, large sums are spent on their destruction. Although many insecticides and acaricides are available, a large number of these have to be used with care because they can endanger animals or because of their phytotoxicity. Moreover, because of their short life cycles, insects and acarids can develop immunity to many of the commonly used insecticides and acaricides and, accordingly, their is always a continuing need for new compounds exhibiting insecticidal and acaricidal properties.
A number of compounds containing the isoxazole system are known to exhibit insecticidal and/or acaricidal activity. For example, Japanese patent specification (published for opposition) No. 45367/78 discloses a class of compounds which may be represented by the formula: ##STR2## in which: R.sup.a represents a hydrogen atom, a lower alkyl group or a halogen atom; and R.sup.b, R.sup.c and R.sup.d each represents a lower alkyl group. These compounds are said to be useful for insecticidal and acaricidal compositions, but they have been found to possess insufficient insecticidal activity for practical use.
There has also been proposed in copending U.S. patent application Ser. No. 318,602, filed Nov. 5, 1981, to the present assignees, a series of carbamoyloxyisoxazole derivatives, which may be represented by the formula: ##STR3## (in which: R.sup.e represents a hydrogen or halogen atom; R.sup.f represents a C.sub.1 -C.sub.6 alkyl group; and R.sup.g represents an oxygen or sulphur atom or a sulphinyl or sulphonyl group). These compounds were demonstrated to have good insecticidal activity.
We have now discovered a series of isoxazolinone derivatives which have superior insecticidal activities, particularly systemic activity, to the known compounds and which, in addition, have good acaricidal activity. They are particularly suitable for the control of aphids and mites.